What is a quick release valve used for in an air brake system?

Pick an answer

1. It lets a driver dump the entire air tank at once, something otherwise impossible to do without a service technician present
2. It slows down how quickly the brakes apply once the pedal is pressed
3. It lets air out of the brake chambers quickly when the brakes are released, so the brakes disengage fast instead of dragging
4. It has nothing to do with brake timing, only with the horn circuit

Correct!

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